Induction Chemoimmunotherapy Followed by Consolidative Hypofractionated Radiotherapy for Unresectable Locally...

Purpose/Objective: To evaluate the safety and failure patterns of consolidative hypofractionated thoracic radiotherapy (RT) following induction chemoimmunotherapy in patients with unresectable locally advanced non-small cell lung cancer (LA-NSCLC). Materials/Methods: This retrospective study included 34 patients treated between 2019 and 2025. All patients received induction chemoimmunotherapy followed by consolidative hypofractionated RT based on multidisciplinary tumor board recommendations. The primary endpoint was local recurrence (LR); secondary endpoints were regional recurrence (RR), distant metastasis (DM), overall survival (OS), progression-free survival (PFS), and treatment-related toxicity. Results: Median age was 64 years, and median PD-L1 expression was 20%. Most patients had stage III disease; squamous cell carcinoma (56%) and adenocarcinoma (38%) were the predominant histologies. The most common systemic regimen was carboplatin/paclitaxel plus nivolumab, with a median of four induction cycles. Post-induction response was complete in 21%, partial in 62%, stable in 12%, and progressive in 6%. Median RT dose was 52.5 Gy in 15 fractions, and maintenance immunotherapy was administered in 79%. At a median follow-up of 16.7 months, using cumulative incidence functions with death treated as a competing event, the 1- and 2-year cumulative incidences of local failure were 6.9% and 14.7%, respectively. The corresponding cumulative incidences of regional failure were 10.2% and 18.8%, while distant metastasis incidences were 15.9% and 39.2%. No isolated local or regional recurrences occurred. One- and two-year OS rates were 86% and 81%, and corresponding PFS rates were 76% and 54%. No grade 4-5 RT-related toxicity occurred; one grade 5 immune-related pneumonitis was observed. Conclusions: Consolidative hypofractionated RT following chemoimmunotherapy appears feasible and associated with favorable outcomes, supporting further prospective investigation.